Incandescent electric lamp



J. A. HEANY.

INCANDESCENT ELECTRIC LAMP.

APPLICATION FILED IuLY 29.1916.

Ipmpw, n @muted Feb. 14, 1922.

UNITED STATES JOHN ALLEN HEANY, F NEW YORK, vN'. Y.

INCANDESCENT ELECTRIC LAMP.

Application filed July 29,

To all wlw/m, t may concern Be it known that I, JOHN ALLEN HEANY, a citizen of the United States, residing in the city of New York, county of New York, and State of New York, have invented certain new and useful Improvements in Incandescent Electric Lamps; and I do hereby declare the following to be a' full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to incandescent electric lamps and has for its object to provide an improved lamp which is highly ellicient and has an unusually long life. In my copending application, Serial No. 107,- 367, filed July 3, 1916, there is disclosed a lamp having a` glower comprising a support of highly refractory material possessing great strength at the operating temperature and which is capable of being heated to incandescence by a resistor of refractory metal, such as tungsten or tungsten alloy, the entire glower being made relatively short and of unusually large diameter to reduce the Convection losses." Each of the different forms of the glower disclosed in the aforesaid application involves the use of a radiating surface composed of a material which will radiate a large amount of energy per unit of surface area, such as tungsten, tungsten alloy, carbon or the like. In a second co-pending application, Serial No. 111,992, filed uly 29, 1916,'there is disclosed a similar glower, except that the radiating surface is composed of a material possessing the property of selective radiation, which has a greater light-emitting efliciency than other materials for a given temperature and which is capable of radiating a large percentage of visible rays in its total radiation,

such, for instance, as zirconia, thoria, magnesia, or other refractory compounds. In the present application, the radiating surface is composed of materials taken from both of the aforesaid classes, or, in other words, it is .formed in part of material which is capable of radiating a large amount of energy per unit of surface area and in part by a material possessing the property of selective radiation, and whichv is capable of emitting a large percentage of visible rays in its total radiation. This invention, therefore, contemplates a glower constructed in substantially the same manner as the glowers disclosed in the aforesaid appli- Specification of Letters Patent.

Patented Feb. 14, 1922.

191e. serial No. 111,993.

cations, but involving a radiating surface formed in the manner above stated.

The invention is illustrated in the 'accompanying drawing, in which Fig. l is a front elevation of the improved lamp; and

Figure 2 is a vertical longitudinal section taken through a preferred form of glower for use with the lamp shown in Figure 1.

Referring first to Fig. l, it will be seen that the lamp comprises the usual glass bulb 1 which may be made of any suitable shape. The threaded metallic base 2 is associated with the bulb 1 in the usual manner and is electrically connected with the lead wires 3 and 4. The gloWer proper is shown at A and is supported in the bulb 1 by means of the wires 3 and 4 in any appropriate manner, which` will tend to reduce the' conduction losses through the lead wires.

In Fig. 2, the support a is formed of refractory compound possessing great strength at the operating temperature and the resistor is in the form of a helical coil b of refractory metal, such as tungsten, tungsten alloy, or the like, wound upon the support at. Over the coil b and the support w' there is a layer d of refractory compound which may be similar to the compound used for the support a', or it may be different. In any event, it should possess the property of selective radiation for a portion of its outer surface is exposed, as will hereinafter appear, to form a portion of the radiating surface. Partly embedded in the outer layer d are a plurality of turns e of refractory metal capable of radiating a large amount of energy per unit of surface area. These turns may be a continuation of the coil b and may be connected in series therewith, so that the inner series of turns b and the outer series e constitute'in reality a continuous coil having an inner layer of turns and an outer layer of turns. The outer layer of turns e are spaced apart, so as to expose between them a portion c of the surface of the layer d. The exposed surfaces of the outer turns e in conjunction with the exposed portions c of the layer d constitute the radiating surface and the'inner layer of turns b act as the resistor to heat the support a and the layer d to a state of incandescence. It is obvious that ifthe material of which the support a is` formed possesses the requisite properties for the radiating surface, the

layer d maybe made of the same material 'less than one atmosphere.

as the support a. In any event, the glower should be so constructed that the exposed portions c of its surface possess the property of selective radiation. It will now be noted that in the form of the glower shown in Fig. 2, the radiating surface is formed in part by the material of which the turns e are made and the material of which the layer (Z is made. The radiating surface, therefore, possesses the property of selective radiation, is capable of developing high efficiency on low temperatures, emits a high ercentage of visible rays in the total radiation, and radiates a large amount of energy per unit of surface area.

It is evident that the support and that portion thereof which helps to form the radiating surface may, if desired, be formed of mixtures of the refractory compounds, or any material or mixtures of materials other than the refractory compounds capable of producing the above-mentioned results.

The glower as a whole is made relatively short and of large diameter as compared with the filament of the ordinary strung incandescent lamp, but is, nevertheless, very small in diameter as compared with the size of the bulb. The large diameter of the glower results in a reduction of the convection losses, and is permitted by the inherent strength at operating temperatures of the materials entering into the construction of the glower. The bulb 1 is preferably filledi with an inert gaseous medium of low thermal conductivity such as nitrogen, mercury vapor, or the like under pressure of a little The inert gas under pressure is used to prevent loss by evaporation, based on the well known fact that the evaporation point varies directly as the pressure. To obtain the greatest efficiency the glower must be operated at as high a temperature as possible. By usin an inert gas under pressure the efficiency o this lamp is as great on low candle power lamps as it is on the present high candle power nitrogen filled lamps. This is because of the fact that even in the lower candle power lamps, the glower is of relatively large diameter and the convection .losses are thereby reduced and also due to the fact that this type of lamp suffers but two end losseswhereas in the present type of lamp there are the two end losses and also the losses at the points of support. The

- bed efficiency of this lamp is still further increased by the selective radiation properties of the oxides used in the radiator. It is not necessary however to operate this glower in an inert gas under pressure. It may be operated, but at a lower temperature, in vacuum. Even in vacuum, the lamp would be more efficient than the present tungsten lamps due to the reduction in the end and supporting losses and also due to the selective radiation of the oxides. These factors increase the efficiency of this glower in vacuum so that its efficiency compares most favorably with that of the high candle power nitrogen filled lamps. Whether the glower is operated in an inert gas under pressure or in vacuum, the same efficiency is obtained on low candle powers as on high candle powers.

The glower may be made in various other different forms than -those shown in the drawing, for instance, the support need not be solid, but may be made tubular in shape, under which conditions the glower would operatein substantially the same manner as described above and little or none of the strength would be sacrificed, and the feature of making the glower of large diameter would still be retained. This feature cooperates intimately with the feature of constructing the radiator of the combination of materials specified for they both contribute their share towards producing a lamp of high efficiency and unusually long life.

Furthermore, the exact relation between the support, resistor and radiating surface is immaterial to the invention as is also the exact manner of forming the radiating surface. It is obvious that the radiating surface composed of the two different kinds of materials could be formed in a large number of different ways, the three forms shown in the drawing being merely exemplary.

What I claim is -A relatively short large diameter glower lof the type described for incandescent electric lamps, including a support formed of a refractory compound, a resistor therefor composed of a helix of refractory metal emed therein, and a radiator comprisin a surface of refractory compound in whic is partially embedded a helix of refractory metal.

In testimony whereof I afiix my si ature.

JOHN ALLEN HE NY. 

